CVE-2025-27800
- CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
- Published: 2025-07-28T09:15:34.387
The Episerver Content Management System (CMS) by Optimizely was affected by multiple Stored Cross-Site Scripting (XSS) vulnerabilities. This allowed an authenticated attacker to execute malicious JavaScript code in the victim’s browser.
The Admin dashboard offered the functionality to add gadgets to the dashboard.
This included the “Notes” gadget. An authenticated attacker with the corresponding
access rights (such as “WebAdmin”) that was impersonating the victim could insert
malicious JavaScript code in these notes that would be executed if the victim
visited the dashboard.
Affected products: Version 11.X: EPiServer.CMS.Core (<11.21.4) with EPiServer.CMS.UI (<11.37.5), Version 12.X: EPiServer.CMS.Core (<12.22.1) with EPiServer.CMS.UI (<11.37.3)
Related CVE by CWE
No related CWE found.
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How to fix CVE-2025-27800
Description: The Episerver Content Management System (CMS) by Optimizely was affected by multiple Stored Cross-Site Scripting (XSS) vulnerabilities. This allowed an authenticated attacker to execute malicious JavaScript code in the victim’s browser. The Admin dashboard offered the functionality to add gadgets to the dashboard. This included the “Notes” gadget. An authenticated attacker with the corresponding access […]
Exploit Difficulty: HARD
⏱️ Time to exploit: > 4 hours
🛠️ Required skills: Advanced security expertise
💰 Public exploits: Rare or not public
How to Fix:
- Check if you're running the affected product
- Update to the latest patched version
- If patching is not immediately possible: restrict network exposure, apply least-privilege access
- Test the fix in a staging environment first
- Review logs for signs of exploitation
- Monitor for IOCs (Indicators of Compromise)
- Enable automatic security updates
- Set up vulnerability monitoring
- Review and harden security configurations
Exploit Difficulty Assessment
Vulnerability Timeline
CVE details first published to NVD database
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Detection Rules & IOCs
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No vendor/product data available.